In-line hydraulic pressure relief valve with reversible flow



April 27, 1954 R. sTEvENsoN IN-LINE HYDRAULIC PRESSURE RELIEF VALVE WITH REVERSIBLE FLOW Filed May 13. 1952 2 Sheets-Sheet l ATTORNEY April 27, 1954 R. sTEvl-:NsoN

IN-LINE HYDRAULIC PRESSURE RELIEF VALVE WITH REVERSIBLE FLOW Filed May l5J 1952 2 Shets-Sheet 2 l INVENToR. ROBERT STEVENSON JMM wlw/ Jim/mu' ATTORNEY wml Patented Apr. 27, 1954 IN-LINE HYDRAULIC PRESSURE RELIEF VALVE WITH REVERSIBLE FLOW Robert Stevenson, Barrington, R. I., assignor to Anco, Inc., a corporation of Rhode Island Application May 13, 1952, Serial No. 287,481

6 Claims.

This invention relates to an in-line hydraulic pressure relief valve with reversible flow such as may be used to control the storing of fluid at a predetermined pressure in an accumulator or the like for operating some work unit.

One of the objects of the present invention is to provide an in-line pressure relief valve for a hydraulic pressure system which satisfies the United States Armed Forces specifications of space, weight, eiciency of operation on pressure control and rate of flow at the outlet over the inlet of the valve.

Another object of the present invention is to provide a pressure relief valve of the in-line type which is particularly adaptable to aircraft because it takes up less space, is lighter in weight and due to efficiency of operation is smaller in area for a given rate of flow.

Still another object of the present invention is to provide a hydraulic pressure relief valve in which fluttering of the port controls is completely eliminated.

Still another object of the present invention is to provide an in-line hydraulic pressure relief valve with a reversible ow feature.

And still another object of the present invention is to provide a hydraulic pressure relief valve which is free nov/ing, that is, the volume of fluid passing through the outlet side of the valve will be equal to the volume of fluid entering the inlet side of the valve.

With these and other objects in view, the invention consists of certain novel features of construction which will be more fully described and particularly pointed out in the appended claims.

ln the past hydraulic pressure relief valves had mechanisms which so lled the housing of the valves as to restrict the area allotted to the fiuid, resulting in an oversize valve for a given rate of discharge at the outlet side of the valve over the inlet side of the valve or else the discharge of the fluid was greatly reduced at the outlet side over the iioW at the intake of the valve. The present invention overcomes this objection by providing a novel construction allotting a uniformity of area throughout the valve for fluid flow.

In the past hydraulic pressure relief valves responded to pressures fifteen per cent or more of the initial relief setting. The present novel construction admits of between two and three per cent of the initial relief setting while permitting a wider variety of pressure adjustments than was heretofore possible in a single relief valve. Consequently a smoother flowing valve is provided due to quicker response to pressure 2 changes. An action is naturally harsher when it requires a fifteen percent change in pressure before it will function over an action responding to a two percent change.

Like reference numerals refer to like parts in the accompanying drawings in which:

Figure 1 is a longitudinal sectional view of the new and improved in-line relief valve with reversible flow.

Figure 2 is a longitudinal sectional view similar to Figure 1, showing the primary valve away from its seat.

Figure 3 is a longitudinal sectional view, similar to Figure 1, showing the secondary valve away from its seat.

Figure 4 is a longitudinal sectional view, similar to Figure 1, showing the reversible flow control valve away from its seat.

Figure 5 is a diagrammatic view illustrating one use of the in-line hydraulic pressure relief valve with reversible ow.

With reference to the drawing, reference character IU generally designates the new and improved in-line hydraulic pressure relief valve with reversible ow consisting of an aluminum cylindrical body Il, having a central bore throughout its length comprising an inlet i2 constructed so as to be readily attachable to a fluid conduit with a fluid tight connection. The construction shown including threads I3 is a United States Military specification. Adjacent inlet I2 is a cavity I4 formed by cylindrical wall I5 which is a termination "of chamber I6 formed by cylindrical wall I1. A ledge I8 is formed between inlet I2 and wall I1 due to their difference in diameters. A threaded area 20 is provided in the end of the cylindrical bore opposite inlet I2. A recess 2| is provided between cylindrical Wall II and threaded area 20 in accordance with good manufacturing practices. A wall I9 is formed between cylindrical wall I'I and cylindrical wall I5.

A gland 23 having an external diameter 25 substantially that of body II, may be provided with a geometric formation such as a square or hexagonal to facilitate assembling gland 23 into body II. Adjacent; external diameter 24 is a threaded area 25 adapted to cooperate with threaded area 20 of body I I. A wall 26 is formed between diameter 24 and threaded area 25. A sleeve 21 adjacent threaded area 25 is provided with a groove 28 adapted to house fluid tight packing material illustrated as consisting of a neoprene O ring 30 and a back up ring 3l which prevents the extrusion of O ring 30 when said O ring is subjected to extremely high pressure. Sleeve 21, ring 30 and back up ring 3| are adapted to cooperate with cylindrical wall Il to form a liuid tight seal under extremely high pressure, including ten thousand pounds per square inch. Adjacent sleeve 2l is a wall 32 terminating in a shoulder 33 and an end 3G. Shoulder 33 is provided with a groove 53 adapted to house a luid tight packing; illustrated as comprising a neoprene O ring l. Ports 58 are provided in shoulder 33.

internally, gland 23 consists of an outlet 35 provided with a configuration including threads 3S adapted to form a fluid tight seal when united with a liuid conduit constructed in accordance with United States Military specications. The left hand end of outlet 35 is provided with a chamber 50 and an axial bore 6|'.

A bushing :l0 provided with a bearing surface il having a groove 42 adapted to house duid tight packing material, illustrated as consisting or" a neoprene O ring 43 and a back up ring 34 which prevents extrusion of O ring 43 when said O ring is subjected to extremely high pressure. Bearing surface 13|, O ring d3 and back up ring @ai are adapted to cooperate with cylindrical wall ll to form a fluid tight seal under extremely high pressure. The outside diameter 45 of bushing 40 is smaller than bearing surface 4|, therefore a Wall 3G is formed between them.

Internally, bushing 40 provides a piston seat el for almost its entire length. The left hand end of bushing 40 is provided with an end wall i3 having an axial bore 50 which forms a valve seat 3l in said end wall 40. The base :'52 of end wail d3 abuts wall IS. The end 53 of bushing 40 abuts wall 32. Shoulder 33 of gland 23 engages the right hand end of piston seat 4l. O ring El cooperatingwith piston seat 4l forms a iluid tight seal. Ports 5d and 55 consisting of a multiple number of orices in bushing 40 are provided adjacent either end of said bushing 43. The area of ports 54 and 55 being determined by the volume of fluid to iiow through said ports 54 and Ports 55 are aligned with ports 5B to form an unobstructed area.

A valve insert 62 provided with a shoulder 63 adapted to abut end 34 and a shank 64 adapted to be secured in axial bore 6| is provided with a valve seat 65 and a valve stem bearing 36. The valve seat 65 is formed at the intersection of valve stein bearing 66 with the valve insert face E8.

A valve plug l0 consists of a head 'il beveled to form a valve plug seat 12 and having valve stem 'i3 which has a bore 'i4 and ports l5. is provided wtih a spring seat 16.

Valve stem 'I3 is slidably mounted in valve stem bearing 63 to enable valve plug seat '|2 to engage and disengage valve seat 65.

A piston 30 slidably nts in piston seat lil and is reduced in diameter as at 8| while its extreme end 82 is further reduced in diameter to provide a shoulder 83. End 82 has a groove 84 for purposes, later to be described. A longitudinal bore 35 is provided extending throughout the axial length of piston 80. At its extreme right hand end bore 35 is threaded as at 86. The left hand end of bore 85 is restricted as at 8l providing a shoulder 83 at the intersection of bores 85 and Head il 87. A groove 89- is provided, for purposes later y to be described. v v

A valve plug 90 is secured to endl 82 with its face 0| abutting shoulder 83 and a lock ring $|2 secured in groove 84 abutting its back 33. A

4 beveled valve face 94 is formed in plug 00 and is adapted to engage valve seat 5|.

A valve insert 95 having a groove 00 adapted to house a fluid tight packing, shown as consisting of a neoprene O ring 07 is driven into bore 35 until face 98 of insert 95 abuts shoulder 08. O ring 9'! will form a iiuid tight connection with the wall of bore 85. An axial passageway |0| provided in insert 35 forms a valve Seat 02 at the juncture of passageway |0| and face |03. A lock ring |04 provided with an axial bore |33 is secured in groove S0 abutting face |03.

A valve plug |01 slidably engages longitudinal bore 35 at its largest diameter which is central of its length; with a reduced diameter extending' to the right as at ||0 and to the left as at il! with a beveled valve face ||2 formed therein. Axially plug |37 is provided with bore ||3 and ports H4. Beveled valve face ||2 is adapted to engage and disengage valve seat H32 through axial bore |05. A shoulder It is formed where the largest diameter terminates to form reduced diameter i The area of end |03 is determined by the angle of beveled valve face H2.

A bushing T-shaped is provided with threads i2! in its largest diameter which are adapted. to engage threads 30. The shank |23 of the 'l' projects from the largest diameter forining a shoulder |24 therebetween. An axial bore 25 terminating in a spring retainer |23 is provided in bushing 20. A coil spring I2? is housed in spring retainer |25 on one end and in spring seat lton the other end. A coil spring i223 housed in bore engages shoulder |33 on one end and shoulder |25 on the other end.

A iiow control insert i is driven into cavity ifs with its outside diameter |3| engaging wall l5 and its face |32 abutting ledge I8. A series of ports |33 are provided along the longitudinal axis of ilow control insert |30, providing the area governing the volume of uid permitted to pass from inlet |2 to cavity I4. The axial port E33 is provided with a spring seat |34. A coil spring |35 is provided in bore 8l' with one end abutting face 98 and the other end housed in spring seat |34.

In operation the in-line hydraulic pressure relief valve with reversible liow I0 (see Figure 5) will be placed in a fluid conduit leading from a fluid conduit |4| connecting pump |132 to an accumulator |43 which has a fluid conduit |44 leading to the work done mechanism |45. A return fluid conduit |43 connects the work done mechanism |45 With a reservoir I4? which completes the cycle by having a lluid conduit |43 connected to pump |42. Relief valve I0 has its outlet connected to a fluid conduit leading to reservoir |47.

Referring to all the figures of the drawing. Fluid from pump |42 flowing, for example, at the rate of six gallons per minute at three thousand pounds per square inch will enter inlet l2, pass through ports |33 into cavity I4 and bore 87. At this point in the operation, let it be assumed that the pump is just bringing the pressure from zero to three thousand pounds per square inch. All the valves, namely, valve plugs IDT, 'iii and 90 will be seated. See Figure 1.

The fluid will now into passageway 0| and act against end |0 and beveled valve face I2. Opposing this uid pressure is spring |28 which is adjustable as to the force it exerts by means of bushing |20 having its threads |2 i engaging threads 86 in piston 00. As theforce of the fluid overcomes the force of spring |28, beveled valve face II2 will leave valve seat |02, thereby per mitting the uid to flow into bore 85 forward of valve plug |01, through ports ||4 and bore I|3 in plug |01 into bore 85 behind valve plug |01, into axial bore |25, spring retainer |26 into the space I5| between the end of piston 80 and end 34. As the fluid pressure in space I5| builds up it will force piston 80 to the left (Figures 1 and 2) against the tension of spring |35, thereby moving beveled valve face 94 away from valve seat 5|. This action permits the fluid in cavity I4 to now through axial bore 50 into chamber |52, into ports 54, into chamber I6, through ports 55 and 58 into outlet 35, fluid conduit |50 back into reservoir |41.

It will thus be seen, that at the period of maximum relief, valve I provides a large area for the fluid to flow through, while at the same time providing a valve plug |01 with a sensitive feel in adjustable spring |28 for relieving the surges in the fluid pressure. The present construction encompasses a hydraulic pressure relief valve operable on a two percent change in fluid pressure. Such change being controlled on a smooth flow basis, eliminating the fluttering inherent in other pressure relief valves.

The magnitude of the present invention can best be understood when, by way of example, three thousand pounds per square inch pressure is desired in accumulator |43 and relief valve I0 will begin to function at 2940 p. s. i. maintaining the desired accumulator pressure within extremely close ranges.

The reversible flow feature will now be described. Pump |42 is not operating (for any one of many reasons). Pressure in the accumulator |43 is dropping below the desired pressure, as for example, 3000 p. s. i. However, the pressure in reservoir |41 exceeds 3000 p. s. i. This pressure acting through uid conduit |50, entering outlet 35, enters bore 14 and ports 15, acting on beveled valve seat 12, moving it away from valve seat 65, thereby permitting the fluid to enter chamber |I, and as previously described, force piston B0 to the left, thereby moving valve face 34 away from valve seat 5|.

The fluid entering outlet will also pass through ports 58, 55, chamber I5, ports 54, chamber |52, bore 5|, cavity I4, ports |33, inlet I2,

fluid conduit |40, I4I to accumulator |43. Theref by maintaining the system operable despite a pump failure.

Having illustrated and described one embodiment of the present invention, by way of example, but realizing that structural changes could be made and other examples given without departing from either the spirit or scope of this invention.

What I claim is:

1. in a hydraulic pressure relief valve, a body having a central bore throughout its length comprising an vinlet attachable to a fluid conduit, a cavity adjacentsaid inlet with a ledge formed therebetween, a chamber adjacent said cavity with a wall formed therebetween, a threaded area separated from said cavity by al recess, a gland provided with a threaded area adapted to be united with the threaded area in said body, a sleeve adjacent said threaded area provided with a groove adapted to house a fluid tight packing when cooperating with said chamber in said body, a shoulder adjacent said sleeve with a wall therebetween, a grooverin said shoulder adapted to house a fluid tight packing, ports in said shoulder, an outlet attachable to a fluid CII conduit, an axial bore adjacent said outlet 'terminating in a counterbored area, a bushing provided with a bearing surface having a groove adapted to house a ud tight packing when cooperating with said chamber, a diameteradjacent said bearing surface with a wall therebetween, a piston seat terminating in an end wall having a valve seat provided in an axial bore, said end wall abutting said wall between said cavity and said chamber, the opposite end of said piston seat engageable with said shoulder and forming a fluid tight packing when cooperating with the fluid tight packing in the groove in said shoulder, the end of said bushing abutting the Wall between said shoulder and said sleeve, ports in both ends of said bushing, the ports of one end engageable with the ports in said shoulder', a valve insert provided with a shoulder adapted to fit in said counterbored area having a shank adapted to be secured in the axial bore of said gland, a valve seat and a valve stem bearing provided in said valve insert, a valve plug consisting of a head beveled to a valve plug seat adapted to cooperate with the valve seat in said v valve insert, a stem having a bore and ports,

slidably mounted in said valve stern bearing, a spring seat in said head, a piston slidably mounted in said piston seat having a reduced diameter adjacent a further reduced diameter on one end with a shoulder therebetween, a groove in the last cf said reduced diameters, a longitudinal bore extending throughout the axial length of said piston with a thread in its right hand end, and a restricted bore in its left hand end having a shoulder at the beginning of said restricted bore and a groove in said longitudinal bore, a valve plug secured to said further reduced diameter abutting said shoulder between said reduced diameters, a spring ring in said groove in the last of said reduced diameters abutting said valve plug, a beveled valve face formed in said valve plug, adapted to engage said valve seat in said bushing, a valve insert having a groove adapted to house a fluid tight packing when cooperating with said longitudinal bore, said valve insert being adapted to be secured in said longitudinal bore with one face abutting said shoulder beginning at said restricted bore, a lock ring in said groove in said longitudinal bore abutting the other face of said valve insert, an axial passagewat7 provided with a valve seat in said valve insert, a valve plug slidably mounted in said longitudinal bore, with a reduced diameter having a beveled valve face adapted to engage said valve seat in said axial passageway, a bore and ports in said valve plug, a bushing provided with threads adapted to engage the threads in said piston having an axial bore terminating in a spring retainer, a spring in said spring retainer engaging said spring seat of said valve plug, a spring in said longitudinal bore engaging said bushing on one end and said valve plug on the other end, a flow control insert secured in said cavity having one face abutting said ledge, provided with ports, a spring seat in one port and a spring in said restricted bore engaging said spring seat on one end and said valve insert on the other end.

2. In a hydraulic pressure relief valve, a body having an inlet provided with means to be secured to a fluid conduit, a cavity adjacent said inlet, a chamber adjacent said cavity, a gland secured in said chamber having means to provide a fiuid tight seal therebetween, a shoulder having ports provided in said gland, an outlet 7 in said gland provided with means to be secured to a iluid conduit, a valveinsert secured in said outlet having a valve seat and a valve stem bearing, a valve plug slidably mounted inv said valve stem bearing having a valve plug seat engageable with the valve seatv in said valve insert, a bush-- ing secured in said chamber having means to'provide a fluid tight seal therebetween, one end of said bushing engaging said shoulder and having means to provide a iluid tight sealy therebetween, ports in said bushing engagingV ports in said shoulder, part of the outside diameterY of' said bushing disengaging said chamber, ports in' theend of said bushing away from saidI first men-- tioned ports, an end wall in said bushing pro-- vided with a valve seat, a piston slidably mount-V ed in said bushing provided with means for se-v curing thereto a valve plug having a valve seat engageable with said valve seat in said bushing, a longitudinal bore throughout the length of said piston, a valve insert secured in said longitudinal bore having means to provide a fluid tight seal therebetween and having an axial bore provided with a valve seat, a valve plug' slidably mounted in said longitudinal bore provided with a valve seat adapted to cooperate with the valve seat in said valve insert having a bore and ports, a bushing secured in said longitudinal bore having an axial bore, resilient means interposed between said bushing and said valve plug, resilient means interposed between said bushing and said first named valve plug, a flow control insert se cured in said cavity having ports and resilient means located in said longitudinal bore engaging said ilow control insert and said valve insert.

3. In an in-line hydraulic pressure relief valve with reversible flow an aluminum body Ihaving an inlet provided with means to form a fluid tight seal when connected with a fluid conduit, a cavity adjacent said inlet, a chamber adjacent said cavity, an aluminum gland provided with means to be secured to said aluminum body with a high pressure iiuid tight seal, a shoulder projecting from said gland having ports, an outlet in said gland provided with means to form a iluid tig-ht seal when connected with a fluid' conduit, a high carbon steel valve insert provided with a valve seat and a valve stem bearing secured in said outlet, a high carbon steel valve plug slidably mounted in said valve stem bearing having a valve plug seat engageable withY they valve seat in said valve insert, av high carbon steel bushing provided with a bearing surface having means to form a high pressure fluid tight seal when secured in said chamber, one end of said bushing having means to form a high pressure fluid tight seal when secured to the shoulder projecting from said gland, the other end of said bushing being provided with a valve seat, two sets of ports in said bushing, one set of ports being in aligned engagement with the ports in said shoulder, a high carbon steel piston slidably' mounted in said bushing having a reduced'diameter secured to a valve plugY provided with a valve seat engageable with` the valve'seat in said bushing, a longitudinal bore throughout the length of said piston, a bushing adjustably mounted in said piston providedY with an axial bore, a valve insert havingv means to provide a high pressure fluid tight seal when secured in said longitudinal bore provided with an axial bore having a valve seat, au valve plugy slidably. mounted insaid longitudinalborehaving,a valve seat engageablewith the valve seat' insaid valve insert and axially having a bore with' p'orts.

resilient means interposed between said valve plug and said adjustably mounted bushing, resilient means interposed between said adjustably mounted bushingv and said iirst mentioned valve plug, a flow control insert secured in said cavity provided with ports and resilient means interposed between said ow control insert and said valve insert.

4. In an in-line hydraulic pressure relief valve with reversible ilow a body'formed with an axial bore having an-inlet in one end and a' gland1 having'an outlet secured in theV other end, a bushing secured in saidy axial bore and forming. a chainber therewith, ports in said bushing communicating with said chamber on. one end and with' said outlet on the other end, annular packing' rings interposed between said bushing and said axial bore: on oneend and between said gland and said axial bore on the other end, a piston having an axial passageway and a reduced outside diameter slidably mounted in said bushing, said reduced outside diameter forming a chamber with said bushing, a valve secured to said reduced outside diameter, a valve slidably mounted in said' axialV passageway, a valve slidably mounted insaid outlet, a chamber formed between the end of said piston and the end of said gland, fluid under pressure in said chamber under' control of said second valve and said third valve controlling said nrst valve, all the valves res'iliently mounted to yield at a predetermined pressure.

5. In an in-line hydraulic pressure relief' valve with reversible flow a body provided with an inletV having an axial bore throughout its. length, a bushing'secured in said axial bore andY forming a chamber therewith, av glandsecured inn said axialy bore provided with an outlet and restricting the length of said chamber, a piston slidably mounted in said bushing4 forminga chamber'with said bushing, a valve on said pistonI for controlling theiiuid flowing. into said chamber, ports insaid bushing connecting said rst chamber' with said second chamber, an axial passageway throughout the length of said piston', a valve' in said. axial passageway controlling.' the iluid flowing through said axial passagewavlabushing having anlaxial bore-'secured in"l one end`- cfsaid' axial passageway, a chamber! formed between the. end of saidpiston and bushing andv said gland, a valve slidably 'mounted in said gland. outlet for controllingy theA fluid entering said last mentioned chamber from said outlet, the fluid in said last mentioned cham-V ber controlling the movement of said second mentioned valve'and ports in said gland and said ,y bushing; connectingl said first mentionedchamber with saidoutlet and resilient means for. each of: the three-valves controlling thepressure at which the said valves will function.

6. In an in-line hydraulic pressure relief valve with reversible flow, a bodyhaving an inlet and a central bore throughout its length, a gland secured in said central bore having an outlet, a chamber adjacentsaid outlet terminating in anA axial bore, a bushing secured in said central` bore on one end and secured to said gland on the other end with a chamber formed between the outside diameter ofr said' bushing and said central bore, a valveseatformed in-one end of said bushing, a piston slidably mounted in said bushing having a reduced. end piston forming. a chamber with said bushing, a valve seat secured. to said reduced endengageable with said valve seat' in ofv said piston, aL valve insert secured in said axial bore, having an axial passageway, a valve seat formed in said axial passageway, a valve plug provided with ports and a valve seat slidably mounted in said axial bore, engageable with said valve seat in said valve insert, a bushing provided with an axial bore secured in said axial bore of said piston, resilient means interposed between said bushing and said valve plug, a valve insert having a valve seat secured in the axial bore of said gland, a valve plug provided with ports and a valve seat slidably mounted in said valve insert, resilient means between said valve plug and said bushing, a iow control insert provided with ports secured in said central bore, resilient means interposed between said flow control insert and said valve insert, ports in either end of said bushing communicating with the chamber formed between said bushing and said body and the chamber formed between the reduced end of said piston and said bushing on one end and with said chamber in said gland on the other end.

References Cited in the le of this patent UNITED STATES PATENTS Number Name Date 2,555,334 Green June 5, 1951 

